No carbs on these S-Types

 

Thanks for the link. Here's the results you were referring to:



Note in the AKI column, which is the rating system we use here in the colonies, the actual increase over the base 91 value of the gas. What a waste of money!!!

 

now im averaging 16 i think and 21 if i use cruise control

 

my 2001 vibrates at idle when i use anything below 93 octane, i changed the coils and have not used 89 or 91 octane again.

 

I guess that I do not understand someone buying a $45,000 car and being cheap on the fuel it requires....ugh

A neighbor complains all the time that his Lincoln Continental knocks all the time and has random check engine lights, and gets a lot less mpg than he expected. He always runs the cheapest gas he can find....

I have pleaded with him to run premium for two tanks to "try it" and see the results...he instead buys some octane booster or seafoam and dumps it in the tank. I told him it would probably be cheaper to just by premium...go figure.....ouch!

 

Since I've owned my S Type - a couple of times I've gotten caught by stations selling premium gas that I'm pretty sure was really 87 octane. My gas mileage went South, and, her performance got real soggy. I also discovered that the engine in our 10 Honda CRV has a CR of 11:1. I started feeding it 93 as well. Its fuel economy improved enough to more than offset the higher fuel cost.

Regards:
Oldengineer

 

For what it is worth. I get about a .1 of a mpg increase when I use premium gas. I use a test loop of 65 miles that consists of: mountain 10% highway 60% and city 30%. I do the drive every weekday. The milage has shown minimal increase with premium in both my A6 twin turbo and my NA S type. No knocks or pings and no noticeable performance loss either. For me it is a waste of money to buy premium for less than 1.84 miles more range per tank full.

 

^ No offense remind me never to buy a car off people whom ignore what the manufacture states for the car.

 

I haven't been around long enough to consider entering this debate. Just an observation of a bit of irony here though. When the subject of other fluids comes up, practically everyone agrees not to skimp and use the best available that meets or exceeds manufacturer spec. I'm talking engine oil, the magic trans fluid, antifreeze ect. But for fuel it would seem whatever will make it run. Not taking a stand here just find it interesting.

 

I agree with both of these comments.

 

I can see the 'it's not worth saving a dollar or four' point of view especially as applied to an expensive luxury car, but asking the question as to ' if I do use it, what happens and why' is far smarter that living in ignorance or believing in 'the sky is falling' myths.

Ignorance is rarely bliss.

 

To each their own, really. But if you're running cheap gas why not run cheap oil? I mean it's "probably" fine right? Why not cheap out on air filters, tires, coolant, spark plugs and so on? It's such a neglibile cost I just don't understand the reluctance.

 

What the heck. I just poured a fresh cup of coffee. I chime in with my own two cents :-)

IMHO....

1) The sole purpose of high octane fuel fuel is to prevent detonation. If your driving conditions or habits are not condusive to creating detonation the anti-detonation benefit of higer octane isn't being utilized. If your car has knock sensors the management system will retard the timing if detonation DOES occur, thus preventing damage. If detonation isn't occuring the management system doesn't know and doesn't care what octane fuel you are using.

2) Lower octane fuel isn't necessarily the same as lower quality fuel. Quality and octane are two different things. It's perfectly easy to buy high quality lower octane fuel.

3) When in doubt, following manufacturer recommendations is always the safest bet. That said, manufacturers' interests and owners' interests are not always the same thing as both can be self-serving.

4) For many owners there's a "feel good" factor to using expensive premium grade [gas/oil/coolant/wax/filters/trans fluid/tire dressing/spark plugs/whatever] even if the benefits are nebulous. I count myself as a member of that group...at times, at least.

Cheers
DD

 

You've equated low octane gas with low quality gas. No connection whatsoever.

Thanks Doug for typing all that, saved me the trouble .

 

Cheap = lower price. For example I would say "that car is cheaper than that one."

Pennywise, pound foolish. And I'm done.

 

Does anyone know what the compression ratio is on the newer S-Types??

Id bet it's high enough the require the gas they suggest. You bought luxury, why treat it like economy??

 

The problem is these cars have falling into a budget buyers market now. So the tightwads are buying them and treating them like a KIA.

 

It's truly sad. I may have paid about 15K for my S-Type but I treat it like I paid 150K.

 

I do know this from my hot rod experiance. An engine with alluminum heads or completely alloy, can tolerate an additional point of compression over a cast iron version. The safe limit for a cast iron engine is widely accepted to be 9.5-1 on premium pump fuel. So an alluminum engine would tolerate 10.5 -1 on the same fuel. This is with old technology...carbs, distributor ign ect. and everything tuned properly. Camshaft profile also has an effect on the cylinder pressure which effects the detonation level.

My TR8 is has the Rover Alloy engine and I have it bumped to 10-1. I run premium in it. The stock engine was 8-1 and probably would have run on kerosene.

I'm not sure what this has to do with the discussion. Probably not much given the electronic management systems involved on newer cars.

Another question that I would pose is what fuel does the 3.0 require in Ford trim?

 

I just bought my S-type about a week ago, and the first tank I filled it up with, was the regular/low-grade/whatever it's called gas. Realized earlier today, that my dad's always put premium in his S-type, so I should probably be doing the same. I'm on a little bit of a budget, which is kinda obvious seeing how I bought an '00 with 105K miles, but I still don't mind paying a few extra bucks for the premium.

What I'm wondering though, and it's probably a stupid question, is if the previous owners had been cheap, and only used the low grade for the previous ten years, will it do any harm for me to switch to premium grade? Kinda like how if you've been a vegetarian forever eating meat will make you sick?